Research progress on the relationship and mechanisms of obesity, gut microbiota, and natural medicines

Obesity has become a major global public health challenge, affecting more than 1.5 billion people worldwide and markedly increasing the risk of chronic diseases, including type 2 diabetes mellitus (T2DM), cardiovascular diseases, and metabolic dysfunction-associated steatotic liver disease (MASLD). In recent years, the gut microbiota has emerged as a critical regulator of host metabolism, immune homeostasis, and energy balance and has been increasingly implicated in the development and pathogenesis of obesity. In obesity, gut microbial diversity often declines and community composition shifts (e.g., increased Firmicutes/Bacteroidetes ratio), which can disrupt energy homeostasis, promote lipid accumulation, trigger chronic inflammation, and alter appetite regulation. This review highlights evidence that natural medicines - including purified phytochemicals, standardized herbal extracts, and traditional multi-herb formulas - can mitigate obesity by beneficially reshaping the gut microbiota. Key mechanisms identified include restoration of microbial balance, increased production of short-chain fatty acids (SCFAs), enhancement of intestinal barrier integrity, and modulation of the gut-brain axis. However, most current evidence derives from preclinical studies; well-controlled human trials of microbiota-targeted natural therapies are still limited, and causal links between specific microbiota shifts and obesity outcomes remain to be established. Collectively, these findings provide a rationale for developing microbiota-oriented natural therapeutic strategies for obesity.